I propose to study the involvement of kinetoplast or mitchondrial DNA in the biosynthesis of mitochondrial enzymes that occurs during the life cycle transformation of T. brucei from the mammaliam bloodstream form to the insect or culture form. This study will involve several subprojects: 1. Obtaining a reproducible, synchronous transformation system that is amenable to quantitative study. Quantitation of the process in terms of synthesis of mitochondrial enzymes, RNA and DNA. 2. Mitochondrial RNA and protein synthesis in the culture form and in the presumably inactive bloodstream form. These studies can be done in vivo using specific antibiotics and in vitro using purified kinetoplast-mitchondrial complexes. 3. Mitochondrial RNA and protein synthesis during the active phase of mitochondrial biogenesis that occurs in the transformation from the bloodstream form to the culture form. In each case mitochondrial ribosomes will be isolated and the mitochondrial ribosomal RNA characterized. Mitochondrial messenger RNA's will be isolated from the transforming cells by a poly A-binding method. The transcriptional origin of the M-RNA's will be studied by hybridization to the K-DNA minicircles and to the K-DNA higher complexity component (if present). My working hypothesis is that the K-DNA minicircles represent an amplified genetic unit that is essential for the transformation process, so far as the transformation involves extensive mitochondrial biogenesis. This genetic unit could represent structural genes for mitochondrial polypeptides, genes for mitochondrial ribosomal RNA, or a unit involved in regulation. The kinetoplast DNA of the hemoflagellates may indeed provide a unique system to study the role and control of the mitochondrial genome.